The impact of viral respiratory tract infections on long-term morbidity and mortality following lung transplantation: a retrospective cohort study using a multiplex PCR panel

Impact of SARS-CoV-2-Related Hygiene Measures on Community-Acquired Respiratory Virus Infections in Lung Transplant Recipients in Switzerland

Background and Objectives: Community-acquired respiratory virus (CARV) infections pose a serious risk for lung transplant recipients (LTR) as they are prone to severe complications. When the COVID-19 pandemic hit Switzerland in 2020, the government implemented hygiene measures for the general population. We investigated the impact of these measures on the transmission of CARV in lung transplant recipients in Switzerland. Materials and Methods: In this multicenter, retrospective study of lung transplant recipients, we investigated two time periods: the year before the COVID-19 pandemic (1 March 2019-29 February 2020) and the first year of the pandemic (1 March 2020-28 February 2021). Data were mainly collected from the Swiss Transplant Cohort Study (STCS) database. Descriptive statistics were used to analyze the results. Results: Data from 221 Swiss lung transplant cohort patients were evaluated. In the year before the COVID-19 pandemic, 157 infections were diagnosed compared to 71 infections in the first year of the pandemic (decline of 54%, p < 0.001). Influenza virus infections alone showed a remarkable decrease from 17 infections before COVID-19 to 2 infections after the beginning of the pandemic. No significant difference was found in testing behavior; 803 vs. 925 tests were obtained by two of the three centers during the respective periods. Conclusions: We observed a significant decline in CARV infections in the Swiss lung transplant cohort during the first year of the COVID-19 pandemic. These results suggest a relevant impact of hygiene measures when implemented in the population due to the COVID-19 pandemic on the incidence of CARV infections.

Lymphocytic Airway Inflammation in Lung Allografts

Lung transplant remains a key therapeutic option for patients with end stage lung disease but short- and long-term survival lag other solid organ transplants. Early ischemia-reperfusion injury in the form of primary graft dysfunction (PGD) and acute cellular rejection are risk factors for chronic lung allograft dysfunction (CLAD), a syndrome of airway and parenchymal fibrosis that is the major barrier to long term survival. An increasing body of research suggests lymphocytic airway inflammation plays a significant role in these important clinical syndromes. Cytotoxic T cells are observed in airway rejection, and transcriptional analysis of airways reveal common cytotoxic gene patterns across solid organ transplant rejection. Natural killer (NK) cells have also been implicated in the early allograft damage response to PGD, acute rejection, cytomegalovirus, and CLAD. This review will examine the roles of lymphocytic airway inflammation across the lifespan of the allograft, including: 1) The contribution of innate lymphocytes to PGD and the impact of PGD on the adaptive immune response. 2) Acute cellular rejection pathologies and the limitations in identifying airway inflammation by transbronchial biopsy. 3) Potentiators of airway inflammation and heterologous immunity, such as respiratory infections, aspiration, and the airway microbiome. 4) Airway contributions to CLAD pathogenesis, including epithelial to mesenchymal transition (EMT), club cell loss, and the evolution from constrictive bronchiolitis to parenchymal fibrosis. 5) Protective mechanisms of fibrosis involving regulatory T cells. In summary, this review will examine our current understanding of the complex interplay between the transplanted airway epithelium, lymphocytic airway infiltration, and rejection pathologies.

Viral infections in lung transplantation

Viral infections account for up to 30% of all infectious complications in lung transplant recipients, remaining a significant cause of morbidity and even mortality. Impact of viral infections is not only due to the direct effects of viral replication, but also to immunologically-mediated lung injury that may lead to acute rejection and chronic lung allograft dysfunction. This has particularly been seen in infections caused by herpesviruses and respiratory viruses. The implementation of universal preventive measures against cytomegalovirus (CMV) and influenza (by means of antiviral prophylaxis and vaccination, respectively) and administration of early antiviral treatment have reduced the burden of these diseases and potentially their role in affecting allograft outcomes. New antivirals against CMV for prophylaxis and for treatment of antiviral-resistant CMV infection are currently being evaluated in transplant recipients, and may continue to improve the management of CMV in lung transplant recipients. However, new therapeutic and preventive strategies are highly needed for other viruses such as respiratory syncytial virus (RSV) or parainfluenza virus (PIV), including new antivirals and vaccines. This is particularly important in the advent of the COVID-19 pandemic, for which several unanswered questions remain, in particular on the best antiviral and immunomodulatory regimen for decreasing mortality specifically in lung transplant recipients. In conclusion, the appropriate management of viral complications after transplantation remain an essential step to continue improving survival and quality of life of lung transplant recipients.

Gastroesophageal Reflux and Esophageal Motility Disorder After Lung Transplant: Influence on the Transplanted Graft

BACKGROUND

Esophageal pathology has been identified as a bad prognostic factor in lung transplantation (LTx). This study aims to assess the esophageal disorders present post-LTx, under treatment with proton pump inhibitors, and their putative impact on the graft.

METHODS

Prospective, observational study of LTx patients. Digestive factors were assessed by manometry and pH-metry at 6 months post-LTx and under proton pump inhibitor treatment. We assessed the association between esophageal disorders and graft function and acute rejection (AR) and chronic lung allograft dysfunction (CLAD).

RESULTS

Out of 76 post-LTx patients, 27% showed gastroesophageal reflux disease (GERD), 55% showed inadequate gastric inhibition, and 59% showed esophageal motility disorders (EMDs). We observed a greater incidence of AR from 3 months post-LTx in the presence of EMD (P ≤ .05). No significant differences were observed in GERD or EMD prevalence or in survival between patients with or without CLAD. The maximum forced expiratory volume in 1 second (FEV1) achieved after bilateral LTx was significantly (P = .022) lower in patients with EMD vs without EMD.

CONCLUSION

At 6 months post-LTx, there is a high percentage of esophageal disorders (GERD and EMDs). No esophageal disorder is associated with CLAD or with survival, although EMDs are associated with a greater incidence of AR and lower graft function.

Lack of clinical significance for molecular detection of respiratory viruses in bronchoalveolar lavage samples

The clinical significance of molecular detection of respiratory viruses in bronchoalveolar lavage (BAL) samples is poorly defined. We performed an observational retrospective study including all patients who underwent a BAL procedure in our institution, regardless of the reason for bronchoscopy, from January 2015 to December 2018. Respiratory viruses were detected by real-time polymerase chain reaction with a commercial multiplex panel, and a cell culture was performed to detect cytomegalovirus and herpes simplex virus. Positive results were correlated with clinical symptoms and patients' characteristics. Of 540 BAL samples analyzed, 113 (20.9%) were positive for any respiratory virus. Viral detection was significantly associated with respiratory symptoms (83.2% vs. 68.9%, p = .004) and radiological infiltrates (67.3% vs. 52.2%, p = .006). The most frequent viruses detected were rhinovirus (42/113, 37.2%), influenza virus (20/113, 17.7%), and parainfluenza virus (PIV) (16/113, 14.2%). Respiratory pathogens codetections were found in 51/113 (45.1%) BAL samples, including more than one virus (16/51, 31.4%), fungi (8/51, 15.7%), and bacteria (9/51, 17.6%). Viral detection was significantly higher in immunocompromised patients (26.5% vs. 16.9%; p = .022). PIV and human metapneumovirus were mostly observed in lung (50.0%, 8/16) and hemopoietic transplant recipients (25%, 2/8), respectively, with clinical repercussions. Our data underline that molecular diagnosis allows identification of viral agents as the etiology of respiratory infections; however, the high frequency of codetections hinders identification of the agent responsible for the current respiratory symptomatology. Immunocompromised patients are the target population in whom to investigate the presence of respiratory viruses in their BAL samples.

Incidence, management and outcome of respiratory syncytial virus infection in adult lung transplant recipients: a 9-year retrospective multicentre study

OBJECTIVES

To analyse functional outcome parameters according to antimicrobial treatments after respiratory syncytial virus (RSV)-confirmed infection in adult lung transplant recipients.

METHODS

A 9-year retrospective multicentre cohort study (2011-19) included adult lung transplant recipients with RSV-confirmed infection. The first endpoint determined new allograft dysfunction (acute graft rejection and chronic lung allograft dysfunction (CLAD)) 3 months after infection. Then baseline and 3 months' postinfection forced expiratory volume in 1 second (FEV₁) values were compared according to antimicrobial treatment. Univariate logistic regression analysis was performed.

RESULTS

RSV infection was confirmed in 77 of 424 lung transplant recipients (estimated incidence of 0.025 per patient per year; 95% confidence interval 0.018-0.036). At 3 months, 22 recipients (28.8%) developed allograft dysfunction: ten (13%) possible CLAD, six (7.9%) acute rejection and six (7.9%) CLAD. Recipients with the lowest preinfection FEV₁ had a greater risk of developing pneumonia (median (interquartile range) 1.5 (1.1-1.9) vs. 2.2 (1.5-2.4) L/s, p 0.003) and a higher odds of receiving antibiotics (1.6 (1.3-2.3) vs. 2.3 (1.9-2.5) L/s, p 0.017; odds ratio 0.52, 95% confidence interval 0.27-0.99). Compared to tracheobronchitis/bronchiolitis, RSV-induced pneumonia led more frequently to hospitalization (91.7%, 22 vs. 58.0%, 29, p 0.003) and intensive care unit admission (33.3%, 8 vs. 0, p < 10^-3). For ribavirin-treated recipients (24.7%, 19) and azithromycin prophylaxis (50.6%, 39), 3-month FEV₁ values were not different from untreated recipients. The overall mortality was 2.5% at 1 month and 5.3% at 6 months, unrelated to RSV.

CONCLUSIONS

At 3 months after RSV-confirmed infection, 22 recipients (28.8%) had new allograft dysfunction. Ribavirin treatment and azithromycin prophylaxis did not prevent FEV₁ decline.

Community-acquired respiratory viruses

PURPOSE OF REVIEW

Incidence of community-acquired respiratory viruses (CARVs) after lung transplantation (LTx) is 10-68 cases per 100 patient-years. Infected patients may develop graft failure and there seems to be an association between CARV infection and development of chronic lung allograft dysfunction (CLAD). This review summarizes the impact of CARV infection after LTx and potential treatment strategies.

RECENT FINDINGS

Detection rate of CARV depends on diagnostic methods. CARV infections after LTx are reported more frequently probably attributed to improved diagnostic methods, especially nucleic acid testing. Paramyxoviridae and picornaviridae are most frequent. For paramyxoviridae, the association with CLAD is reported in various single-center observational studies. Neuraminidase inhibitors are approved for influenza and can be safely used in flu-infected LTx patients. There is no approved treatment for paramyxoviruses, most centers use ribavirin in the infected LTx recipient.

SUMMARY

Antivirals against CARV in LTx recipients have not yet demonstrated reduced morbidity in randomized clinical trials. Agents against CARV under development are inhibiting viral attachment and use silencing mechanisms of viral replication. The cohort of lung transplant recipients is a focus of intense research because of the high morbidity of CARV infection and intense surveillance of LTx recipeints.

Respiratory viral infection in lung transplantation induces exosomes that trigger chronic rejection

BACKGROUND

Respiratory viral infections can increase the risk of chronic lung allograft dysfunction after lung transplantation, but the mechanisms are unknown. In this study, we determined whether symptomatic respiratory viral infections after lung transplantation induce circulating exosomes that contain lung-associated self-antigens and assessed whether these exosomes activate immune responses to self-antigens.

METHODS

Serum samples were collected from lung transplant recipients with symptomatic lower- and upper-tract respiratory viral infections and from non-symptomatic stable recipients. Exosomes were isolated via ultracentrifugation; purity was determined using sucrose cushion; and presence of lung self-antigens, 20S proteasome, and viral antigens for rhinovirus, coronavirus, and respiratory syncytial virus were determined using immunoblot. Mice were immunized with circulating exosomes from each group and resulting differential immune responses and lung histology were analyzed.

RESULTS

Exosomes containing self-antigens, 20S proteasome, and viral antigens were detected at significantly higher levels (p < 0.05) in serum of recipients with symptomatic respiratory viral infections (n = 35) as compared with stable controls (n = 32). Mice immunized with exosomes from recipients with respiratory viral infections developed immune responses to self-antigens, fibrosis, small airway occlusion, and significant cellular infiltration; mice immunized with exosomes from controls did not (p < 0.05).

CONCLUSIONS

Circulating exosomes isolated from lung transplant recipients diagnosed with respiratory viral infections contained lung self-antigens, viral antigens, and 20S proteasome and elicited immune responses to lung self-antigens that resulted in development of chronic lung allograft dysfunction in immunized mice.

Epidemiology and clinical impact of viral, atypical, and fungal respiratory pathogens in symptomatic immunocompromised patients: a two-center study using a multi-parameter customized respiratory Taqman® array card

The prevalence of respiratory viruses in immunocompromised adult patients and the association with clinical outcomes is still underexplored. Our goal was to assess the epidemiology and the potential clinical impact of respiratory viral infections in a high-risk patient population. Two large hospitals performed a respiratory Taqman array card (TAC), targeting 24 viruses, 8 bacteria, and 2 fungi simultaneously, on 435 samples from 397 symptomatic immunocompromised patients. Clinical details were collected retrospectively using a structured case report form. An overall positivity rate of 68% was found (51% mono- and 17% co-infections). Pathogen distribution was as follows: influenza A (20.7%), rhinoviruses (15.2%), coronaviruses (7.8%), Pneumocystis jirovecii (7.4%), RSV (7.1%), and CMV (6.0%) were the most frequently encountered, followed by HSV (5.5%), hMPV (4.4%), parainfluenza viruses (3.9%), influenza B (3.7%), and Aspergillus species (3.7%). Other pathogens were not detected or detected only in ≤ 1% of samples. Hospital and ICU admission rates were 84% and 11%, respectively. The presence of a pathogen was strongly associated with higher need for supplemental oxygen (p = 0.001), but it had no impact on ICU admission, mechanical ventilation requirement, antibacterial therapy, or mortality. In conclusion, our study described the epidemiology of respiratory pathogens in a large group of symptomatic immunocompromised patients and provides evidence of a relationship between pathogen detection and the need for supplemental oxygen. This association was still found after the exclusion of the results positive for influenza viruses, suggesting that non-influenza viruses contribute to severe respiratory illness in patients with compromised immunity.

Practical Guidance for Clinical Microbiology Laboratories: Viruses Causing Acute Respiratory Tract Infections

Respiratory viral infections are associated with a wide range of acute syndromes and infectious disease processes in children and adults worldwide. Many viruses are implicated in these infections, and these viruses are spread largely via respiratory means between humans but also occasionally from animals to humans. This article is an American Society for Microbiology (ASM)-sponsored Practical Guidance for Clinical Microbiology (PGCM) document identifying best practices for diagnosis and characterization of viruses that cause acute respiratory infections and replaces the most recent prior version of the ASM-sponsored Cumitech 21 document, Laboratory Diagnosis of Viral Respiratory Disease, published in 1986. The scope of the original document was quite broad, with an emphasis on clinical diagnosis of a wide variety of infectious agents and laboratory focus on antigen detection and viral culture. The new PGCM document is designed to be used by laboratorians in a wide variety of diagnostic and public health microbiology/virology laboratory settings worldwide. The article provides guidance to a rapidly changing field of diagnostics and outlines the epidemiology and clinical impact of acute respiratory viral infections, including preferred methods of specimen collection and current methods for diagnosis and characterization of viral pathogens causing acute respiratory tract infections. Compared to the case in 1986, molecular techniques are now the preferred diagnostic approaches for the detection of acute respiratory viruses, and they allow for automation, high-throughput workflows, and near-patient testing. These changes require quality assurance programs to prevent laboratory contamination as well as strong preanalytical screening approaches to utilize laboratory resources appropriately. Appropriate guidance from laboratorians to stakeholders will allow for appropriate specimen collection, as well as correct test ordering that will quickly identify highly transmissible emerging pathogens.

Viral Respiratory Tract Infection During the First Postoperative Year Is a Risk Factor for Chronic Rejection After Lung Transplantation

Supplemental digital content is available in the text.

Background

Chronic lung allograft dysfunction (CLAD) is the major limiting factor for long-term survival in lung transplant recipients. Viral respiratory tract infection (VRTI) has been previously associated with CLAD development. The main purpose of this study was to evaluate the long-term effects of VRTI during the first year after lung transplantation in relation to CLAD development.

Method

Ninety-eight patients undergoing lung transplantation were prospectively enrolled between 2009 and 2012. They were monitored for infections with predefined intervals and on extra visits during the first year, the total follow-up period ranged between 5 and 8 years. Nasopharyngeal swab and bronchoalveolar lavage samples were analyzed using a multiplex polymerase chain reaction panel for respiratory pathogens. Data regarding clinical characteristics and infectious events were recorded.

Results

Viral respiratory tract infection during the first year was identified as a risk factor for long-term CLAD development (P = 0.041, hazard ratio 1.94 [1.03-3.66]) in a time-dependent multivariate Cox regression analysis. We also found that coronavirus in particular was associated with increased risk for CLAD development. Other identified risk factors were acute rejection and cyclosporine treatment.

Conclusions

This study suggests that VRTI during the first year after lung transplantation is associated with long-term CLAD development and that coronavirus infections in particular might be a risk factor.

Transplanting the pulmonary virome: Dynamics of transient populations

BACKGROUND

Lung transplantation provides a unique opportunity to investigate the dynamics of the human pulmonary virome that is transplanted within the donor lungs. The pulmonary virome comprises both "resident" and "transient" viruses. In this study we aimed to analyze the dynamics of the "transient" members.

METHODS

We conducted a single-center, prospective, longitudinal investigation of community-acquired respiratory viruses detected in nasopharyngeal swabs, swabs of explanted and donor lungs, and serial bronchoalveolar lavages post-transplant.

RESULTS

Fifty-two consecutive lung transplant recipients were recruited (bilateral:heart‒lung:bilateral lung-liver = 48:2:2) (age [mean ± SD] 48 ± 15 years, range 20 to 63 years; 27 males and 25 females). Follow-up was 344 ± 120 (range 186 to 534) days. Seventeen of 45 explanted lungs were positive for influenza A and/or B (A = 14, B = 2, A+B = 1), despite recipient vaccination and negative nasal swabs, and 4 of 45 had human rhinovirus and 2 of 45 parainfluenza. Donor swabs showed influenza (A = 1, B = 1) and rhinovirus (n = 3). Day 1 lavage showed influenza A (n = 28), rhinovirus (n = 9), and parainfluenza (n = 1). Forty-seven of 52 recipients had a positive lavage for virus (38 of 47 on multiple lavages). Influenza persisted for 59 ± 38 (range 4 to 147) days in 27 of 52, and 14 had a single isolate. Rhinovirus persisted for 95 ± 84 (range 22 to 174) days in 13 of 52, and 13 had a single isolate. Analysis of 118 paired transbronchial biopsies and lavage demonstrated no association between viruses and acute cellular rejection (Fisher's exact test, 2 tailed, p = 1.00).

CONCLUSIONS

Using a sensitive uniplex polymerase chain reaction we found that the transplanted pulmonary virome often includes community-acquired respiratory viruses, including influenza, which are variably persistent but not associated with acute rejection.

Community-Acquired Respiratory Viruses

The incidence of community-acquired respiratory viruses (CARVs) is ∼15 cases per 100 patient-years after lung transplantation (LTx). Paramyxoviruses account for almost 50% of the cases of CARV infection in LTx. Most patients will be symptomatic with a mean decline of 15 to 20% in forced expiratory volume in 1 second. The attributable death rate is low in recent years 15 to 25% CARV infected LTx patients will develop chronic lung allograft dysfunction within a year after CARV infection. This risk seems to be increased in comparison to the noninfected LTx recipient.

Detection rate of CARV dependent on clinical awareness, sampling, and diagnostic method with nucleic acid testing by polymerase chain reaction in bronchoalveolar lavage is the gold standard after LTx.

There is no approved treatment for paramyxoviruses, most centers use ribavirin by various routes. Toxicity of systemic ribavirin is of concern and some patients will have contraindication to this treatment modality. Treatment may reduce the risk to develop chronic lung allograft dysfunction and respiratory failure. Agents under development are inhibiting viral attachment and use silencing mechanisms of viral replication.

Long-term outcomes and management of lung transplant recipients

Lung transplantation is an established treatment for patients with end-stage lung disease. Improvements in immunosuppression and therapeutic management of infections have resulted in improved long-term survival and a decline in allograft rejection. Allograft rejection continues to be a serious complication following lung transplantation, thereby leading to acute graft failure and, subsequently, chronic lung allograft dysfunction (CLAD). Bronchiolitis obliterans syndrome (BOS), the most common phenotype of CLAD, is the leading cause of late mortality and morbidity in lung recipients, with 50% having developed BOS within 5 years of lung transplantation. Infections in lung transplant recipients are also a significant complication and represent the most common cause of death within the first year. The success of lung transplantation depends on careful management of immunosuppressive regimens to reduce the rate of rejection, while monitoring recipients for infections and complications to help identify problems early. The long-term outcomes and management of lung transplant recipients are critically based on modulating natural immune response of the recipient to prevent acute and chronic rejection. Understanding the immune mechanisms and temporal correlation of acute and chronic rejection is thus critical in the long-term management of lung recipients.

Metagenomic sequencing complements routine diagnostics in identifying viral pathogens in lung transplant recipients with unknown etiology of respiratory infection

Background

Lung transplant patients are a vulnerable group of immunosuppressed patients that are prone to frequent respiratory infections. We studied 60 episodes of respiratory symptoms in 71 lung transplant patients. Almost half of these episodes were of unknown infectious etiology despite extensive routine diagnostic testing.

Methods

We re-analyzed respiratory samples of all episodes with undetermined etiology in order to detect potential viral pathogens missed/not accounted for in routine diagnostics. Respiratory samples were enriched for viruses by filtration and nuclease digestion, whole nucleic acids extracted and randomly amplified before high throughput metagenomic virus sequencing. Viruses were identified by a bioinformatic pipeline and confirmed and quantified using specific real-time PCR.

Results

In completion of routine diagnostics, we identified and confirmed a viral etiology of infection by our metagenomic approach in four patients (three Rhinovirus A, one Rhinovirus B infection) despite initial negative results in specific multiplex PCR. Notably, the majority of samples were also positive for Torque teno virus (TTV) and Human Herpesvirus 7 (HHV-7). While TTV viral loads increased with immunosuppression in both throat swabs and blood samples, HHV-7 remained at low levels throughout the observation period and was restricted to the respiratory tract.

Conclusion

This study highlights the potential of metagenomic sequencing for virus diagnostics in cases with previously unknown etiology of infection and in complex diagnostic situations such as in immunocompromised hosts.

Risks and Epidemiology of Infections After Lung or Heart–Lung Transplantation

Nowadays, lung transplantation is an established treatment option of end-stage pulmonary parenchymal and vascular disease. Post-transplant infections are a significant contributor to overall morbidity and mortality in the lung transplant recipient that, in turn, are higher than in other solid organ transplant recipients. This is likely due to several specific factors such as the constant exposure to the outside environment and the colonized native airway, and the disruption of usual mechanisms of defense including the cough reflex, bronchial circulation, and lymphatic drainage. This chapter will review the common infections that develop in the lung or heart–lung transplant recipient, including the general risk factors for infection in this population, and specific features of prophylaxis and treatment for the most frequent bacterial, viral, and fungal infections. The effects of infection on lung transplant rejection will also be discussed.

Symptomatic Respiratory Virus Infection and Chronic Lung Allograft Dysfunction

Background. Chronic lung allograft dysfunction (CLAD) is a major cause of allograft loss post-lung transplantation. Prior studies have examined the association between respiratory virus infection (RVI) and CLAD were limited by older diagnostic techniques, study design, and case numbers. We examined the association between symptomatic RVI and CLAD using modern diagnostic techniques in a large contemporary cohort of lung transplant recipients (LTRs).

Methods. We retrospectively assessed clinical variables including acute rejection, cytomegalovirus pneumonia, upper and lower RVI, and the primary endpoint of CLAD (determined by 2 independent reviewers) in 250 LTRs in a single university transplantation program. Univariate and multivariate Cox models were used to analyze the relationship between RVI and CLAD in a time-dependent manner, incorporating different periods of risk following RVI diagnosis.

Results. Fifty patients (20%) were diagnosed with CLAD at a median of 95 weeks post-transplantation, and 79 (32%) had 114 episodes of RVI. In multivariate analysis, rejection and RVI were independently associated with CLAD (adjusted hazard ratio [95% confidence interval]) 2.2 (1.2–3.9), P = .01 and 1.9 (1.1–3.5), P = .03, respectively. The association of RVI with CLAD was stronger the more proximate the RVI episode: 4.8 (1.9–11.6), P < .01; 3.4 (1.5–7.5), P < .01; and 2.4 (1.2–5.0), P = .02 in multivariate analysis for 3, 6, and 12 months following RVI, respectively.

Conclusions. Symptomatic RVI is independently associated with development of CLAD, with increased risk at shorter time periods following RVI. Prospective studies to characterize the virologic determinants of CLAD and define the underlying mechanisms are warranted.

Strategies for safe living among lung transplant recipients: a single-center survey

BACKGROUND

Lung transplant (LT) recipients are at high risk for infection owing to lifelong immunosuppression and direct communication of the graft with the environment. Guidelines have been established for safe-living strategies after transplantation. We conducted a survey of LT patients to determine compliance with these strategies.

METHODS

Adult LT outpatients completed a survey consisting of questions on a 5-point Likert scale with the following categories: hand washing, gardening, respiratory infections, food and water safety, animal contact, travel, and occupation.

RESULTS

A total of 194 LT recipients completed the survey (age 54.4 ± 13.3 years; time post transplant 4.76 ± 3.5 years). Regular hand washing was practiced usually or always by 87.6%. Of those who worked with soil/gardened, 70/99 (70.7%) never wore a mask and 15.7% never wore gloves. Pet ownership was common (52%), but most patients used specific precautions during handling. Over one-third of patients continued employment after transplant but, of these, 56% had modified their occupation often because of perceived infectious risks. Most patients were fully compliant with influenza vaccination (92.3%). Patients <40 years of age were less likely to wear long-sleeved clothing in mosquito season (P = 0.002), more likely to handle pet feces (P = 0.005), and less likely to wear a mask with sick contacts (P = 0.021).

CONCLUSIONS

We provide important insight into safe-living practices following lung transplantation and identify specific areas and subgroups of patients that could be targeted for enhanced education, with potential significant clinical benefit.

Viral PCR positivity in stool before allogeneic hematopoietic cell transplantation is strongly associated with acute intestinal graft-versus-host disease

Acute graft-versus-host disease (aGVHD) can be triggered by inflammatory conditions, including infections and mucositis. We investigated the association between PCR positivity for gastrointestinal (GI) viruses in stool before hematopoietic cell transplantation (HCT) and intestinal aGVHD using Cox proportional hazard models. We included 48 consecutive HCT patients (28 with malignancies and 20 with nonmalignancies) without GI symptoms before HCT. Fifteen patients were GI virus positive: 9 adenovirus, 3 norovirus, 2 parechovirus, and 1 astrovirus. Overall survival was 58% ± 8%. The cumulative incidence of aGVHD grade 2 to 4 was 43% ± 8% (n = 18) after a median of 47 days (range, 14 to 140). In univariate analysis, GI virus PCR positivity was the only predictor for aGVHD (P = .008): within the group of GI virus PCR-positive patients, the cumulative incidence of aGVHD 2 to 4 was 70% ± 12% versus 29 ± 8% in the PCR-negative group (P = .004). In conclusion, GI virus PCR positivity before HCT predicted development of intestinal aGVHD. These results may ultimately affect monitoring, aGVHD prophylaxis, and treatment, as well as rescheduling of elective HCTs.

Lower respiratory tract virus findings in mechanically ventilated patients with severe community-acquired pneumonia

BACKGROUND

The role of viral infections in the etiology of severe community-acquired pneumonia (SCAP) was prospectively evaluated from 2008 to 2012 at a university-level intensive care unit.

METHODS

Clinical data and microbiological tests were assessed: blood cultures, urine pneumococcal and legionella antigens, Mycoplasma pneumoniae and Chlamydia pneumoniae antibodies from paired serums, and respiratory virus detection by multiplex, real-time polymerase chain reaction (PCR) from nasopharyngeal swabs and lower tracheal specimens via intubation tube.

RESULTS

Of 49 mechanically ventilated SCAP patients (21 men and 28 women; median age, 54 years), the etiology was identified in 45 cases (92%). There were 21 pure bacterial infections (43%), 5 probably pure viral infections (10%), and 19 mixed bacterial-viral infections (39%), resulting in viral etiology in 24 patients (49%). Of 26 viruses, 21 (81%) were detected from bronchial specimens and 5 (19%) from nasopharyngeal swabs. Rhinovirus (15 cases, 58%) and adenovirus (4 cases, 15%) were the most common viral findings. The bacterial-viral etiology group had the highest peak C-reactive protein levels (median, 356 [25th-75th percentiles, 294-416], P = .05), whereas patients with probably viral etiology had the lowest peak procalcitonin levels (1.7 [25th-75th percentiles, 1.6-1.7]). The clinical characteristics of pure bacterial and mixed bacterial-viral etiologies were comparable. Hospital stay was longest among the bacterial group (17 vs 14 days; P = .02).

CONCLUSIONS

Viral findings were demonstrated in almost half of the SCAP patients. Clinical characteristics were similar between the pure bacterial and mixed bacterial-viral infections groups. The frequency of viral detection depends on the availability of PCR techniques and lower respiratory specimens.

Factors associated with bronchiolitis obliterans syndrome and chronic graft-versus-host disease after allogeneic hematopoietic cell transplantation

Bronchiolitis obliterans syndrome (BOS) is a form of chronic graft vs. host disease (cGVHD) and a highly morbid pulmonary complication after allogeneic hematopoietic stem cell transplantation (HSCT). We assessed the prevalence and risk factors for BOS and cGVHD in a cohort of HSCT recipients, including those who received reduced intensity conditioning (RIC) HSCT. Between January 1, 2000 and June 30, 2010, all patients who underwent allogeneic HSCT at our institution (n = 1854) were retrospectively screened for the development of BOS by PFT criteria. We matched the BOS cases with two groups of control patients: (1) patients who had concurrent cGVHD without BOS and (2) those who developed neither cGVHD nor BOS. Comparisons between BOS patients and controls were conducted using t-test or Fisher's exact tests. Multivariate regression analysis was performed to examine factors associated with BOS diagnosis. All statistical analyses were performed using SAS 9.2. We identified 89 patients (4.8%) meeting diagnostic criteria for BOS at a median time of 491 days (range: 48-2067) after HSCT. Eighty-six (97%) of our BOS cohort had extra-pulmonary cGVHD. In multivariate analysis compared to patients without cGVHD, patients who received busulfan-based conditioning, had unrelated donors, and had female donors were significantly more likely to develop BOS, while ATG administration was associated with a lower risk of BOS. Our novel results suggest that busulfan conditioning, even in RIC transplantation, could be an important risk factor for BOS and cGVHD.

Outcome of respiratory syncytial virus lower respiratory tract disease in hematopoietic cell transplant recipients receiving aerosolized ribavirin: significance of stem cell source and oxygen requirement

Respiratory syncytial virus (RSV) infection is an important complication after hematopoietic cell transplantation (HCT), and RSV lower respiratory tract disease (LRD) results in substantial early mortality and late airflow obstruction among survivors. Factors associated with poor outcome are unknown. We evaluated the effect of transplant and treatment factors on overall survival, mortality from respiratory failure, and pulmonary function among 82 HCT recipients who had RSV LRD between 1990 and 2011. All patients received aerosolized ribavirin. In multivariable analyses, only the use of marrow or cord blood as graft source (adjusted hazard ratio [aHR], 4.1; 95% confidence interval [CI], 1.8 to 9.0; P < .001) and oxygen requirement (aHR, 3.3; 95% CI, 1.5 to 6.7; P = .003) remained independently associated with overall mortality and death due to respiratory failure (aHR, 4.7; 95% CI, 1.8 to 13; P = .002 and aHR, 5.4; 95% CI, 1.8 to 16; P = .002, respectively). Antibody-based treatments, including intravenous immunoglobulin and palivizumab, were not independently associated with improved outcome and did not alter the associations of the graft source and oxygen requirements in statistical models. In conclusion, use of peripheral blood stem cells as graft source and lack of oxygen requirement at diagnosis appear to be important factors associated with improved survival of HCT recipients with RSV LRD. These results may explain differences in outcomes reported from RSV infection over time and may guide the design of future interventional trials.